The present invention relates to a resin composition which is excellent in the impact resistance, moldability, weather resistance and chemical resistance and which is useful for an injection molded product, an extrusion molded product, a film, a sheet, etc., its molded product and a damping material made of the resin composition.
A polyolefin such as polyethylene or polypropylene is a typical general purpose plastic and has been used in a large amount for household products. For example, polyethylene or polypropylene is excellent in e.g. mechanical strength, moldability, heat resistance and chemical resistance and thus is used in various fields as a general purpose resin for e.g. films or containers. Further, in recent years, high performance polyolefin has become obtainable by an improvement in the polymerization technology for polyolefins, and it has been attempted to use it in a field where an engineering plastic has heretofore been used. However, its impact resistance is inadequate, and it has been difficult to employ it as an automobile part material such as a bumper or an instrument panel, or as a housing part material for a household product such as a refrigerator or a washing machine.
In the field of transparent soft resins, a so-called soft vinyl chlorine resin is widely used. However, as it contains chlorine, an environmental load resulting from incineration has become problematic. Accordingly, a substitute material for such a vinyl chlorine resin is desired.
On the other hand, an aromatic vinyl compound type resin such as a styrene type resin or a rubber-reinforced styrene type resin is a material excellent in the dimensional stability and rigidity, but has a drawback that it is inferior in the mechanical property, particularly in toughness.
For the purpose of overcoming such a drawback, a method is known in which an olefin type elastomer such as ethylene/isobutene is, for example, incorporated to a polyolefin. However, there will be a drawback that the surface hardness tends to decrease, and the surface tends to be susceptible to scratching. A resin composition with an ethylene/xcex1-olefin copolymer has a drawback such that it is inferior in the transparency.
For an aromatic vinyl compound type resin, it is common to employ a method of dispersing a rubber phase having elasticity non-continuously in a hard resin for the purpose of improving the impact resistance. At that time, it is common to add e.g. a styrene/butadiene random copolymer, a styrene/butadiene block copolymer, a styrene/isoprene block copolymer or a hydrogenated styrene/butadiene block copolymer. However, there is a drawback such that the resin is likely to undergo thermal deterioration during molding due to the double bond of butadiene or isoprene of the copolymer, or in the case of a styrene/butadiene block copolymer or the like, the styrene blocks have no solvent resistance, and the resin tends to be inferior in the solvent resistance. Further, the hydrogenated styrene/butadiene block copolymer has a problem that the rigidity of the resin composition tends to substantially decrease.
From such a background, a polymer composition is desired wherein different properties, such as high rigidity and glass transition temperature of an aromatic vinyl compound type polymer, flexibility and low glass transition point of an olefin polymer, and a high solvent resistance attributable to a crystal structure, are well balanced. However, heretofore, a composition obtained by blending an aromatic vinyl compound type polymer and an olefin type polymer, has not provided the desired physical properties, since compatibility of these resins is poor. Therefore, various compatibilizing agents have been studied. As a compatibilizing agent, a block copolymer of an aromatic vinyl compound with a diene compound or SEBS having such a copolymer hydrogenated, has been, for example, employed. (J. Polym. Sci., Polym. Letters, 19, 79 (1981), JP-A-56-38338, U.S. Pat. No. 4,020,025, etc.) Further, a case wherein styrene butadiene rubber (SBR) or hydrogenated SBR is employed as a compatibilizing agent, has also been reported.
Recently, as a copolymer made of an aromatic vinyl compound monomer and an olefin type monomer, a styrene/ethylene solid random copolymer is disclosed in JP-A-7-70223 or U.S. Pat. No. 5,703,187. Such a pseudorandom copolymer is a copolymer obtained by means of a geometrically constrained catalyst (CGCT catalyst). According to JP-A-6-49132, it is superior to a styrene type block copolymer in the compatibility with other resins. However, the pseudorandom copolymer contains no head-to-tail chain structure of aromatic vinyl compound units, and accordingly, the compatibility tends to be limited. Further, no significant stereoregularity is observed, and it is a non-crystalline resin in a region where the styrene content is at least from 15 to 20 mol %, whereby the mechanical property such as breaking strength is not sufficient, and the solvent resistance is also not sufficient.
WO98/10015 discloses a composition comprising an intercopolymer of an aromatic vinylidene monomer with an xcex1-olefin monomer and a polyolefin, and W098/10014 discloses a composition comprising an intercopolymer of an aromatic vinylidene monomer with an xcex1-olefin monomer and an interpolymer of an aromatic vinylidene monomer or the like. However, Examples of these specifications are directed to pseudorandom copolymers by means of the above-mentioned CGCT catalysts.
Further, JP-A-10-60194 discloses a composition comprising an ethylene/vinylidene aromatic monomer copolymer and a propylene type resin. However, in Examples, the CGCT catalyst is likewise employed.
The present inventors have conducted an extensive study on an aromatic vinyl compound/olefin random copolymer having a true random structure i.e. not a pseudorandom structure and on its physical properties and as a result, have found a method for its production, and they have found that the random copolymer is one provided with the properties of an aromatic vinyl compound type polymer and an olefin type polymer in good balance and further have found a resin composition comprising the random copolymer having overcome the above-mentioned drawbacks of a conventional aromatic vinyl compound type polymer or an olefin type polymer, whereby the present invention has been completed.
Namely, the present invention relates to a resin composition characterized by comprising from 5 to 95 wt % of an aromatic vinyl compound/olefin random copolymer (A) which has an aromatic vinyl compound content of from 1 to 99 mol % and has a head-to-tail chain structure composed of two or more aromatic vinyl compound units, and from 95 to 5 wt % of an xcex1-olefin type polymer (B) and/or an aromatic vinyl compound type polymer (C); a molded product thereof and a damping product thereof.
Now, the present invention will be described in detail.
The aromatic vinyl compound/olefin random copolymer (A) constituting the resin composition of the present invention is such an aromatic vinyl compound/olefin random copolymer (A) having an aromatic vinyl content of from 1 to 99 mol % and has a head-to-tail chain structure composed of two or more aromatic vinyl compound units.
It will be described with reference to a styrene-ethylene random copolymer which is suitably used as the random copolymer (A).
The aromatic vinyl compound/olefin random copolymer constituting the present invention has main peaks at the following positions by 13C-NMR using TMS as standard.
Namely, it shows peaks attributable to main chain methylene and main chain methine carbon in the vicinity of from 24 to 25 ppm, in the vicinity of 27 ppm, in the vicinity of 30 ppm, in the vicinity of from 34 to 37 ppm, in the vicinity of from 40 to 41 ppm and in the vicinity of from 42 to 46 ppm, and peaks attributable to five carbons not bonded to the polymer main chain in the phenyl group in the vicinity of 126 ppm and in the vicinity of 128 ppm, and a peak attributable to one carbon bonded to the polymer main chain in the phenyl group in the vicinity of 146 ppm.
The styrene/ethylene random copolymer to be used in the present invention is a styrene/ethylene random copolymer having a styrene content of from 1 to 99 mol %, preferably from 10 to 90 mol % and is such a styrene/ethylene random copolymer (A2) wherein the alternating structure index xcex of styrene units and ethylene units represented by the following Formula (i) is larger than 1 and smaller than 70, preferably larger than 5 and smaller than 70:
xcex=A3/A2xc3x97100xe2x80x83xe2x80x83(i)
where A3 is the sum of peak areas attributable to three carbons a, b and c of a styrene/ethylene alternating structure represented by the following formula K2, as obtained by the 13C-NMR measurement, and A2 is the sum of peak areas attributable to the main chain methylene and the main chain methine carbon, as observed within a range of from 0 to 50 ppm by 13C-NMR using TMS as standard: 
(wherein Ph is a phenyl group, and x is an integer of at least 2 representing a number of repeating units).
In a styrene/ethylene random copolymer which is preferably employed in the present invention, the stereoregularity of phenyl groups in the styrene/ethylene alternating structure represented by the above formula K3 has an isotactic structure. Here, xe2x80x9chas an isotactic structurexe2x80x9d means a styrene/ethylene random copolymer (A3) wherein the isotactic diad index m (or a meso diad fraction) represented by the following Formula (ii), is larger than 0.5, and preferably means such a random copolymer wherein m is preferably larger than 0.75, more preferably at least 0.95.
Here, Ar is a peak area attributable to the r structure of a methylene carbon peak appearing in the vicinity of 25 ppm, and Am is a peak area attributable to the m structure:
m=Am/(Ar+Am)xe2x80x83xe2x80x83(ii)
The positions of the peaks may sometimes shift more or less depending upon the measuring conditions or the solvent used.
For example, when chloroform-d is used as a solvent, and TMS is used as standard, the peak attributable to the r structure appears in the vicinity of from 25.4 to 25.5 ppm, and the peak attributable to the m structure appears in the vicinity of from 25.2 to 25.3 ppm.
Further, when 1,1,2,2-tetrachloroethane-d2 is used as a solvent, and the center peak (shift value of 73.89 ppm from TMS standard) of the triplet of the 1,1,2,2-tetrachloroethane-d2 is used as standard, the peak attributable to the r structure appears in the vicinity of from 25.3 to 25.4 ppm, and the peak attributable to the m structure appears in the vicinity of from 25.1 to 25.2 ppm.
Here, the m structure represents a meso diad structure, and the r structure represents a racemic diad structure.
In the styrene-ethylene random copolymer to be used in the present invention, a peak attributable to the r structure of the alternating structure of ethylene and styrene is not substantially observed.
Further, in the styrene/ethylene random copolymer which is preferably used in the present invention, the stereoregularity of phenyl groups in the chain structure of styrene units, is isotactic. The stereoregularity of phenyl groups in the chain structure of styrene units being isotactic means a styrene/ethylene random copolymer (A4) wherein the isotactic diad index ms (or a meso diad fraction) represented by the following Formula (iii), is larger than 0.5, and preferably means such a random copolymer wherein ms is preferably at least 0.7, more preferably at least 0.8:
ms=Amxe2x80x2/(Arxe2x80x2+Amxe2x80x2)xe2x80x83xe2x80x83(iii)
where Arxe2x80x2 is a peak area of methylene carbon attributable to the syndiotactic diad structure (r structure) by the 13C-NMR measurement, and Amxe2x80x2 is a peak area of methylene carbon attributable to the isotactic diad structure (m structure).
The stereoregularity of the chain structure of styrene units is determined by the peak position of methylene carbon in the vicinity of from 43 to 44 ppm as observed by 13C-NMR and by the peak position of the main chain proton as observed by 1H-HMR.
With respect to the foregoing xcex, m and ms, the details are disclosed in JP-A-9-309925.
According to U.S. Pat. No. 5,502,133, methylene carbon of an isotactic polystyrene chain structure appears in the vicinity of from 42.9 to 43.3 ppm, but methylene carbon of a syndiotactic polystyrene chain structure appears in the vicinity of from 44.0 to 44.7 ppm. The positions of the sharp peak of methylene carbon of the syndiotactic polystyrene and the broad peak at from 43 to 45 ppm of an atactic polystyrene are close to or overlap the positions of peaks with relatively low intensity of other carbon of the styrene/ethylene random copolymer to be used in the present invention. However, in the present invention, a strong methylene carbon peak is observed from 42.9 to 43.4 ppm, but no clear peak is observed in the vicinity of from 44.0 to 44.7.
The styrene/ethylene random copolymer to be used in the present invention is such a random copolymer containing a chain structure wherein styrene units are bonded head-to-tail, a chain structure wherein ethylene units are bonded to one another and a structure in which aromatic vinyl compound units and ethylene units are bonded. The proportions of these structures in the random copolymer vary depending upon the content of the styrene monomer during the polymerization or polymerization conditions such as the polymerization temperature.
As the styrene content decreases, the proportion of the chain structure in which styrene units are bonded head-to-tail, decreases. For example, in a case of the random copolymer wherein the styrene content is not higher than about 20 mol %, it is difficult to directly observe a peak attributable to the chain structure wherein styrene units are bonded head-to-tail, by the usual 13C-NMR measurement. However, it is evident that the chain structure in which aromatic vinyl compound units are bonded head-to-tail, is present in the copolymer, although the amount may be small, even if the styrene content is not higher than 20 mol %, since it is possible to produce a polystyrene having stereoregularity under high catalytic activity by homopolymerization of styrene by using the transition metal compound as described in the present invention or by the method as described in the present invention, i.e. it is essentially possible to form a chain structure in which styrene units are bonded head-to-tail, and since in the random copolymer, the proportion of the chain structure in which styrene units are bonded head-to-tail, continuously changes corresponding to the styrene content of from 20 to 99 mol % at least by the 13C-NMR method. It is possible to observe the chain structure wherein aromatic vinyl compound units are bonded head-to-tail, in the copolymer having a styrene content of not higher than 20 mol %, by such a means as the 13C-NMR analysis using a styrene monomer enriched with 13C.
The same applies to the chain structure of ethylene units.
The chain structure of a head-to-tail bond of styrene units contained in the styrene/ethylene random copolymer to be used in the present invention is a chain structure of at least two styrenes, preferably a chain structure of at least three styrenes, which can be represented by the following structure K4: 
(wherein n is an integer of at least 2 representing a number of repeating units, and Ph is a phenyl group).
On the other hand, in the conventional so-called pseudo random copolymer, no head-to-tail chain structure of styrene units can be found even in the vicinity of 50 mol % at which the styrene content is maximum. Further, even if homopolymerization of styrene is attempted by using a catalyst for the preparation of a pseudo random copolymer, no polymer is obtainable. Depending upon e.g. the polymerization condition, an extremely small amount of an atactic styrene homopolymer may sometimes be obtained. However, this is considered to have been formed by radical polymerization or cation polymerization by coexisting methylalumoxane or an alkylaluminum included therein.
The weight average molecular weight of the styrene/ethylene random copolymer to be used in the present invention is preferably at least 60,000, preferably at least 80,000, when the styrene content is at least 1 mol % and less than 20 mol %, and at least 30,000, preferably at least 40,000, when the styrene content is at least 20 mol % and at most 99 mol %.
Here, the weight average molecular weight is a molecular weight as calculated as polystyrene, obtained by GPC using standard polystyrene. To have such a practical high molecular weight as shown here, is a condition required particularly when an application as a compatibilizing agent or as a polymer composition is taken into consideration. The upper limit of the weight average molecular weight is not particularly limited, but it is preferably at most 3,000,000, more preferably at most 1,000,000. If the molecular weight exceeds 3,000,000, the melt viscosity increases, and it tends to be difficult to prepare a composition by e.g. a melt kneading method, and further, molding by a common molding method such as injection molding or extrusion molding tends to be difficult.
Further, the molecular weight distribution (Mw/Mn) is at most 6, preferably at most 4, particularly preferably at most 3. As the molecular weight distribution is small, and the homogeneity is high, the transparency is good. Particularly, it is a feature that in comparison with a copolymer obtainable by a CGCT catalyst, the composition distribution is small, and the homogeneity is high, whereby the transparency is high.
The styrene/ethylene random copolymer to be suitably used in the present invention is such that it has a highly stereoregular alternating structure of ethylene and styrene in combination with various structures such as ethylene chains having various lengths, inversion of styrene and head to tail chains of styrene having various lengths. Further, the proportion of the alternating structure can be variously changed by the styrene content in the random copolymer within a range of xcex of the above formula for alternating structure index xcex being more than 1 and less than 70. The stereoregular alternating structure is a crystallizable structure. Accordingly, the random copolymer can be made to have various properties in the form of a polymer having a crystalline, non-crystalline, or partially or microcrystalline structure, by controlling the styrene content or the crystallinity by a suitable method. The value xcex being less than 70 is important in order to impart significant toughness and transparency to a crystalline polymer, or to obtain a partially crystalline polymer, or to obtain a non-crystalline polymer.
As compared with a conventional styrene/ethylene copolymer having no stereoregularity or no styrene chains, the styrene/ethylene random copolymer to be suitably used in the present invention is improved in various properties such as the initial tensile modulus, hardness, breaking strength and solvent resistance in various styrene content regions at various degrees of crystallinity and thus exhibits characteristic physical properties as a crystalline resin, a thermoplastic elastomer or a transparent soft resin.
Further, by changing the styrene content, the glass transition point can be changed within a wide range. Within a styrene content range of at least about 10 mol %, it has a high melting point (by DSC) as compared with the conventional styrene/ethylene pseudorandom copolymer having no stereoregularity or no styrene chains.
Further, as a means to increase the crystallinity, it is possible to adopt a means such as annealing, addition of a nucleating agent or alloying with a polymer having a low Tg (such as wax).
The foregoing description was made with reference to a styrene/ethylene random copolymer as an example. However, the foregoing description applies as it is to an aromatic vinyl compound/olefin random copolymer.
The aromatic vinyl compound to be used for the aromatic vinyl compound/olefin random copolymer (A) constituting the resin composition of the present invention may, for example, be styrene and various substituted styrenes (such as p-methylstyrene, m-methylstyrene, o-methylstyrene, o-t-butyl styrene, m-t-butyl styrene, p-t-butyl styrene, and xcex1-methylstyrene, and may further be, for example, a compound having a plurality of vinyl groups in one molecule, such as divinyl benzene.
Industrially, it is preferred to use styrene, p-methylstyrene or xcex1-methylstyrene, particularly preferably styrene. These aromatic vinyl compounds may be used in combination as a mixture of two or more of them.
Further, the olefin may, for example, be a C2-20 xcex1-olefin, such as ethylene, propylene, 1-butene, 1-hexene, 4-methyl-1-pentene or 1-octene, or a cyclic olefin such as norbornene or norbornadiene. Among them, ethylene or propylene is preferred.
Further, especially in a preferred aromatic vinyl compound/ethylene copolymer, a C3-20 xcex1-olefin such as propylene, 1-butene, 1-hexene, 4-methyl-1-pentene or 1-octene, a cyclic olefin such as norbornene or norbornadiene and/or a diene such as butadiene or isoprene, may be incorporated as a third or fourth monomer component for the purpose of improving the physical properties, so long as the above-mentioned alternating structure index xcex value and the stereoregularity index m value are within the ranges prescribed by the present invention.
Further, depending upon the polymerization conditions, etc., there may be a case where an atactic homopolymer resulting from thermal, radical or cationic polymerization of an aromatic vinyl compound, will be contained in a small amount. However, such an amount is not higher than 10 wt % of the entirety. Such a homopolymer can be removed by solvent extraction, but the product may be used as it contains such a homopolymer, unless there is any particular problem from the viewpoint of the physical properties.
Further, the resin composition of the present invention may be blended with a polymer other than the above described polymers, within a range not to impair the performance of the resin composition.
A method for producing the aromatic vinyl compound/olefin random copolymer (A) to be used in the present invention, is not particularly limited. However, it can be produced from an aromatic vinyl compound and an olefin by means of a catalyst comprising a transition metal compound represented by the following Formula K5 and a co-catalyst with a practically high productivity: 
In the above Formula, A and B are groups selected from an unsubstituted or substituted cyclopentaphenanthryl group (the following K6, K7), an unsubstituted or substituted benzindenyl group (K8 to K10), an unsubstituted or substituted cyclopentadienyl group, an unsubstituted or substituted indenyl group, or an unsubstituted or substituted fluorenyl group, provided that at least one of A and B is a group selected from an unsubstituted or substituted cyclopentaphenanthryl group, an unsubstituted or substituted benzindenyl group, or an unsubstituted or substituted indenyl group. Preferably, at least one of A and B is a group selected from an unsubstituted or substituted cyclopentaphenanthryl group, or an unsubstituted or substituted benzindenyl group. 
(in the above Formulae K6 to K10, each of R1 to R8 is hydrogen, a C1-20 alkyl group, a C6-10 aryl group, a C7-20 alkylaryl group, a halogen atom, an OSiR3 group, a SiR3 group or a PR2 group (each R is a C1-10 hydrocarbon group), and the plurality of R1, the plurality of R2, the plurality of R3, the plurality of R4 and the plurality of R5 may be the same or different from one another.) When each of A and B is an unsubstituted or substituted cyclopentaphenanthryl group, an unsubstituted or substituted benzindenyl group, or an unsubstituted or substituted indenyl group, the two may be the same or different.
Specifically, the unsubstituted cyclopentaphenanthryl group may, for example, be a 3-cyclopenta[c]phenanthryl group or a 1-cyclopenta[1]phenanthryl group.
The unsubstituted benzindenyl group may, for example, be 4, 5-benz-1-indenyl (another name: benzo(e)indenyl), 5,6-benz-1-indenyl or 6,7-benz-1-indenyl, and the substituted benzindenyl group may, for example, be xcex1-acenaphtho-1-indenyl.
In the above Formula K5, Y is a methylene group, a silylene group or an ethylene group, which has bonds to A and B and further has hydrogen or a C1-15 hydrocarbon group. The substituents may be the same or different from one another. Further, Y may have a cyclic structure such as a cyclohexylidene group or a cyclopentylidene group.
Preferably, Y is a substituted methylene group which has bonds to A and B and is substituted by hydrogen or a C1-15 hydrocarbon group. The hydrocarbon group may, for example, be an alkyl group, an aryl group, a cycloalkyl group or a cycloaryl group. The substituents may be the same or different from one another.
Particularly preferably, Y is xe2x80x94CH2xe2x80x94, xe2x80x94CMe2xe2x80x94, xe2x80x94CEt2xe2x80x94, xe2x80x94CPh2xe2x80x94, a cyclohexylidene or a cyclopentylidene group. Here, Me represents a methyl group, Et an ethyl group, and Ph a phenyl group.
In the above Formula K5, X is hydrogen, halogen, a C1-15 alkyl group, a C6-10 aryl group, a C8-12 alkylaryl group, a silyl group having a C1-4 hydrocarbon substituent, a C1-10 alkoxy group, or a dialkylamide group having a C1-6 alkyl substituent. The halogen may, for example, be chlorine or bromine; the alkyl group may, for example, be a methyl group or an ethyl group; the aryl group may, for example, be a phenyl group; the alkylaryl group may, for example, be a benzyl group; the silyl group may, for example, be a trimethylsilyl group; the alkoxy group may, for example, be a methoxy group, an ethoxy group or an isopropoxy group; and the dialkylamide group may, for example, be a dimethylamide group.
Especially when X is dimethylamide, if the production method disclosed in WO95/32979 is applied to the production of the transition metal compound represented by the above Formula K5, there will be a merit that the compound can be produced very simply and at a low cost.
M is zirconium, hafnium or titanium, particularly preferably zirconium. With respect to a transition metal compound where a racemic-form and a meso-form are present, the racemic-form is preferably employed. However, a mixture of the racemic-form and the meso-form, or the meso-form, may be employed.
Specific examples of such a transition metal compound are disclosed in the above-mentioned JP-A-9-309925, and the following compounds may, for example, be mentioned.
For example, dimethylmethylene bis(1-indenyl)zirconium dichloride, dimethylmethylene bis(4,5-benz-1-indenyl)zirconium dichloride (another name: dimethylmethylenebis(benz-e-indenyl)zirconium dichloride), di-n-propylmethlenebis(4,5-benz-1-indenyl)zirconium dichloride, di-i-propylmethylenebis(4,5-benz-1-indenyl)zirconium dichloride, cyclohexylidenebis(4,5-benz-1-indenyl)zirconium dichloride, cyclopentylidenebis(4,5-benz-1-indenyl)zirconium dichloride, diphenylmethylenebis(4,5-benz-1-indenyl)zirconium dichloride, dimethylmethylene(cyclopentadienyl)(4,5-benz-1-indenyl)zirconium dichloride, dimethylmethylene(1-indenyl)(4,5-benz-1-indenyl)zirconium dichloride, dimethylmethylene(l-fluorenyl)(4,5-benz-1-indenyl)zirconium dichloride, dimethylmethylene(4-phenyl-1-indenyl)(4,5-benz-1-indenyl)zirconium dichloride, dimethylmethylene(4-naphthyl-1-indenyl)(4,5-benz-1-indenyl)zirconium dichloride, dimethylmethylenebis(5,6-benz-1-indenyl)zirconium dichloride, dimethylmethylene(5,6-benz-1-indenyl)(1-indenyl)zirconium dichloride, dimethylmethylenebis(4,7-benz-1-indenyl)zirconium dichloride, dimethylmethylene(6,7-benz-1-indenyl)(1-indenyl)zirconium dichloride, dimethylmethylenebis(4,5-naphtho-1-indenyl)zirconium dichloride, dimethylmethylenebis(xcex1-acetonaphtho-1-indenyl)zirconium dichloride, dimethylmethylenebis(3-cyclopenta(c)phenanthryl)zirconium dichloride, dimethylmethylene(3-cyclopenta(c)phenanthryl)(1-indenyl)zirconium dichloride, dimethylmethylenebis(1-cyclopenta(1)phenanthryl)zirconium dichloride, dimethylmethylene(1-cyclopenta(1)phenanthryl)(1-indenyl)zirconium dichloride, and dimethylmethylenebis(4,5-benz-1-indenyl)zirconium bis(dimethylamide), may be mentioned.
In the foregoing, zirconium transition metal compounds were exemplified, but corresponding hafnium and titanium transition metal compounds may also suitably be used. Further, a mixture of the racemic-form and the meso-form may also be employed. Preferably, however, the racemic-form or the pseudo racemic-form is employed. In such a case, D-isomers or L-isomers may be employed.
For the production of the aromatic vinyl compound/olefin random copolymer to be used in the present invention, as the co-catalyst, a co-catalyst which has been used in combination with a transition metal compound, may be employed. As such a co-catalyst, aluminoxane (or alumoxane) or a boron compound is preferably employed.
As the co-catalyst, aluminoxane (or alumoxane) is particularly preferably employed.
A boron compound and an organic aluminum compound may be used simultaneously.
As the aluminoxane, methylalumoxane, ethylalumoxane or triisobutylalumoxane, is preferably employed.
Particularly preferred is methylalumoxane. If necessary, a mixture of these different types of alumoxanes, may be employed. Further, such an alumoxane may be used in combination with an alkylaluminum such as trimethyl aluminum, triethyl aluminum or tri-isobutyl aluminum, or with a halogen-containing alkylaluminum such as dimethylaluminum chloride.
Addition of an alkylaluminum is effective for removing substances which hinder polymerization, such as a polymerization inhibitor in the styrene monomer, or moisture in the solvent, or for removing adverse effects against the polymerization reaction.
When a boron compound is used as a co-catalyst, addition of an alkylaluminum compound such as tri-isobutyl aluminum is effective for the removal of impurities which adversely affect the polymerization, such as water contained in the polymerization system.
For the production of the aromatic vinyl compound/olefin random copolymer to be used in the present invention, the above-mentioned olefin, the aromatic vinyl compound, the transition metal compound catalyst and the co-catalyst are contacted. As to the manner and order for contacting, an optional known method may be employed.
The polymerization temperature is suitably from xe2x88x9278xc2x0 C. to 200xc2x0 C., preferably from 0xc2x0 C. to 165xc2x0 C. A polymerization temperature lower than xe2x88x9278xc2x0 C. is industrially disadvantageous, and if it exceeds 200xc2x0 C., decomposition of the transition metal compound catalyst will take place, such being undesirable. Industrially further preferred is from 30xc2x0 C. to 160xc2x0 C.
The amount of the transition metal compound to be used is preferably such that the molar ratio of double bonds of the total charged monomer to transition metal atoms in the transition metal compound, i.e. the molar ratio of double bonds of the total charged monomer/transition metal atoms, is preferably from 1 to 108, more preferably from 102 to 108.
The details of the random copolymer of the present invention as described in the foregoing, are disclosed in JP-A-9-309925 and DE-19711339A1 by the present inventors, with respect to the transition metal compound catalyst, the co-catalyst and the structural characteristics, to be used for the production. However, the preferred ranges of the m and ms values are as disclosed in the present specification.
The xcex1-olefin type polymer (B) constituting the resin composition of the present invention, is a homopolymer made of a C2-12 xcex1-olefin monomer such as ethylene, propylene, butene, 1-hexene, 4-methyl-1-pentene or 1-octene, or a copolymer made of two or more such monomers. If required, a diene such as butadiene or xcex1, xcfx89-diene may be copolymerized. Namely, it may, for example, be a high density polyethylene (HDPE), a low density polyethylene (LDPE), a linear low density polyethylene (LLDPE) such as an ethylene/1-octene copolymer, an isotactic polypropylene, a syndiotactic polypropylene, a propylene/ethylene random copolymer, a propylene/ethylene block copolymer, an ethylene/propylene copolymer (EPR), an ethylene/propylene/diene copolymer (EPDM) or a propylene/butene copolymer.
Further, a polymer of a cyclic olefin such as cyclopentene, norbornene or norbornadiene or an ethylene/norbornene copolymer which is a copolymer of the cyclic olefin with the above xcex1-olefin, may also be employed.
The foregoing xcex1-olefin type polymer (B) is required to have a weight average molecular weight as calculated as styrene, of at least 30,000, preferably at least 50,000, in order to provide the performance as a practical resin.
The aromatic vinyl compound type polymer (C) constituting the resin composition of the present invention includes a homopolymer of an aromatic vinyl compound and a copolymer of an aromatic vinyl compound with at least one monomer component copolymerizable therewith, wherein the aromatic vinyl compound content is at least 40 wt %.
Aromatic vinyl compound monomers to be used for the aromatic vinyl compound type polymer, may, for example, be styrene and various substituted styrenes such as p-methylstyrene, m-methylstyrene, o-methylstyrene, o-t-butylstyrene, m-t-butylstyrene, p-t-butylstyrene and xcex1-methylstyrene. Further, a compound having a plurality of vinyl groups in one molecule, such as divinyl benzene, may also be mentioned. Further, a copolymer of a plurality of such aromatic vinyl compounds, may also be employed.
Further, the stereoregularity among aromatic groups of aromatic vinyl compounds may be atactic, isotactic or syndiotactic.
The monomer copolymerizable with the aromatic vinyl compound may, for example, be butadiene, isoprene or other conjugated dienes, acrylic acid, methacrylic acid, an amide derivative, an ester derivative or maleic anhydride. The copolymerization type may be a block copolymer or a random copolymer.
Further, it may be one having the above aromatic vinyl compound graft-polymerized to a polymer made of the above monomer, which contains at least 50 wt % of the aromatic vinyl compound. As such an example, a high impact polystyrene (HIPS) may, for example, be mentioned which includes a di- or tri-block copolymer such as a styrene/isoprene block copolymer (SIPS) or a styrene/butadiene block copolymer (SBS), or a hydrogenated block copolymer such as a hydrogenated styrene/butadiene/styrene block copolymer (SEBS) or a hydrogenated styrene/isoprene/styrene block copolymer (SEPS).
By employing, among them, a methacrylate/styrene copolymer, an acrylonitrile/styrene copolymer, a rubber-reinforced methacrylate/styrene copolymer, a rubber-reinforced acrylonitrile/styrene copolymer or a methacrylate/butylene/styrene copolymer, having a styrene content of at least 30 wt %, as the copolymer (C), more preferably by employing such a copolymer (C) having a refractive index of from 1.52 to 1.59, it is possible to obtain a resin composition of the present invention excellent in transparency, whereby the haze value in a thickness of 1 mm is not more than 50.
The foregoing aromatic vinyl compound type polymer (C) is required to have a weight average molecular weight as calculated as styrene, of at least 30,000, preferably at least 50,000, to provide the performance as a practical resin.
The resin composition of the present invention comprises from 5 to 95 wt % of the aromatic vinyl compound/olefin random copolymer (A) and from 5 to 95 wt % of the xcex1-olefin type polymer (B) and/or the aromatic vinyl compound type polymer (C). The polymers (B) and (C) are incorporated alone or in combination in an amount of from 5 to 95 wt %. Preferred blending is such that when either one of (B) and (C) is employed, (A):(B)=10 to 90 wt %:90 to 10 wt %, or (A):(C)=10 to 90 wt %:90 to 10 wt %, and when both (B) and (C) are employed, (A):(B):(C)=5 to 50 wt %:5 to 90 wt %:5 to 90 wt %. In these ranges, particularly good effects can be obtained.
The component (A) to be used for the resin composition of the present invention may be a combination of plural members different in the styrene content ratio, the molecular weight and the molecular weight distribution. Further, also the components (B) and (C) may likewise be combinations of plural members.
To prepare the polymer composition of the present invention, a known suitable blending method may be employed. For example, melt-mixing can be carried out by means of e.g. a single screw or twin screw extruder, a Henschel mixer, a Banbury mixer, a plastomill, a co-kneader or a heat roll mill. Prior to the melt-mixing, it is advisable to mix various materials uniformly by means of e.g. a Henschel mixer, a ribbon blender, a super mixer or a tumbler. The melt-mixing temperature is not particularly limited, but it is usually from 100 to 300xc2x0 C., preferably from 150 to 250xc2x0 C. The resin composition of the present invention can be utilized as a product such as a sheet, a film, a blow-molded product, an injection-molded product or a heat press molded product.
A method for producing a sheet may, for example, be extrusion molding of e.g. T-die or inflation system, press molding or casting, and if necessary, stretching may be carried out. As a method for forming a foam, a physical method by means of a gas or a low boiling point hydrocarbon or a chemical method by means of an inorganic blowing agent, an organic blowing agent or a decomposition-type agent formed by a thermal decomposition of ammonia, water, nitrogen or carbon dioxide gas, may, for example, be mentioned. The inorganic blowing agent may, for example, be sodium hydrogencarbonate, ammonium carbonate or ammonium hydrogencarbonate. The organic blowing agent may, for example, be azodicarbonamide, azobisformamide or azobisisobutyronitrile.
Further, the obtained sheet or film may be subjected to secondary processing to obtain a container or a packaging material having excellent physical properties of the resin composition of the present invention.
The sheet is not particularly limited with respect to the thickness, a single layer, a multi layer or a layer structure. However, the thickness is preferably from 1 xcexcm to 10 mm, particularly preferably from 5 xcexcm to 3 mm. The container is also not limited with respect to the shape and the content.
The resin composition of the present invention exhibits excellent impact resistance, moldability, weather resistance or chemical resistance. This is believed to be attributable not only to the fact that the aromatic vinyl compound/olefin random copolymer (A) constituting the resin composition is per se excellent in the impact resistance, moldability, weather resistance or chemical resistance, but also to the fact that it has a head-to-tail chain structure of the aromatic vinyl compound in its molecule and effectively serves as a modifying agent or a compatibilizing agent for the xcex1-olefin type polymer (B) and/or the aromatic vinyl compound type polymer (C), so that the random copolymer (A) and the xcex1-olefin type polymer (B) and/or the aromatic vinyl compound type polymer (C) are supplemented to each other.
To the resin composition of the present invention, a known heat resistant stabilizer, weather resistant stabilizer, aging-preventing agent, anti-static agent, coloring agent, lubricant, softening agent, filler such as glass fiber, silica or talc, and a plasticizer may, for example, be incorporated as the case requires, within a range not to impair the performance of the resin composition.
Further, the resin composition of the present invention may be cross-linked by dynamic vulcanization in the presence of an organic peroxide, or under irradiation with electron rays or radiation rays.
The resin composition of the present invention can be used as a damping material which comprises from 5 to 99.5 wt % of such a resin composition and from 0.5 to 95 wt % of an inorganic filler, whereby the loss tangent tan xcex4 of a dynamic viscoelasticity measured at a frequency of 1 Hz within a temperature range of from xe2x88x92100xc2x0 C. to +100xc2x0 C., is from 0.2 to 1.0. The ratio of the resin composition to the inorganic filler is preferably 10 to 99 wt %:1 to 90 wt %, more preferably 20 to 90 wt %:10 to 80 wt %. The range of the loss tangent tan xcex4 is preferably from 0.5 to 8.0, more preferably from 1.0 to 6.0. Further, by using the aromatic vinyl compound/olefin random copolymers (A) to be used for the resin composition of the present invention, in a combination of plural members different in the styrene content ratio, the molecular weight, the molecular weight distribution, etc., it is also possible to obtain excellent damping properties within a wide temperature range.
Molded products made of the damping material of the present invention may be used for e.g. vibration-reducing parts for e.g. office appliances, household products such as washing machines, automobiles, machine tools, industrial machines or audio instruments such as speaker materials, for floor materials, for wall materials, or for sealing materials. In a case of a product having a flat surface structure such as a film, a sheet, a tile or a board, like a floor material, a wall material or a sealing material, it may be of a single layer structure or a multi layer structure. Products of other shapes may also have multi layer structures, as the case requires. In the case of a multi layer structure, it is possible to use in the respective layers the aromatic vinyl compound/olefin random copolymers (A) differing in the composition, the compositional distribution, the molecular weight, the molecular weight distribution, etc., the compositions of the present invention differing in the filler or the type or content of the flame retarder, other resin components, materials, etc. The aromatic vinyl/olefin random copolymers (A) are different in the peak temperatures of loss tangent (tan xcex4) depending upon the copolymerization ratios, and accordingly, by laminating a plurality of copolymers having mutually different copolymerization ratios, it is possible to obtain vibration-suppressing performance within a wide temperature range. In such a case, the copolymerization ratio is required to be different by at least 2%, preferably at least 5% by molar fraction.
Further, in the case of a multi layer structure, the number of layers is not particularly limited, but it is preferably from 2 to 10 layers, more preferably from 2 to 5 layers.
The resin composition of the present invention contains substantially no chlorine and is excellent in the impact resistance, moldability, weather resistance and chemical resistance, and it is useful for an injection molded product, an extrusion molded product, a film, a sheet, etc. Further, it provides an excellent damping material.